A mysterious sticky substance covering more than 100 birds which washed up on the coast of southern England could be palm oil dumped in the sea.

The Royal Society for the Protection of Birds (RSPB) was called in on Thursday after the troubled guillemots, a member of the auk family, were discovered on Lyme Bay near Weymouth, Dorset.

The seabirds were taken to West Hatch Animal Centre in Taunton, Somerset, but early attempts to clean them have been hampered by not knowing what the thick, white, substance is, said the RSPB's Grahame Madge.

Many were found on the shores of Chesil Cove in Dorset, but others appeared up to 200 miles away in Cornwall.

An investigation is continuing and Mr Madge said: "We could be dealing with quite a large incident as all these birds could be proved to come from the same pollution incident."

Sky's Ashish Joshi, reporting from Chesil Cove, said more of the birds have been washing up on the shore this morning.

He said of the RSPB: "They think it might be palm oil which has been dumped in a container load out there somewhere."

Joshi added: "If the birds get to this shoreline, they're exhausted, they're unable to fly, they can't get back into the water so their chances of survival are near to minimal.

"So it's important that members of the local community, including the RSPB, are coming to this shoreline and finding these birds."

The spokesman said: "We would urge people to be cautious going down to the coastline affected.

"The instinctive reaction is to go down and look, or to help out. But we don't know what this substance is, so our message is for people - especially those taking dogs down to the coastline - to please be careful."